<Item type="Activity" action="edit" where="[ACTIVITY].name='@2' and [ACTIVITY].id in (select related_id from [WORKFLOW_PROCESS_ACTIVITY] where source_id=(select related_id from [WORKFLOW] where source_id='@1'))">
 <Relationships>
  <Item type="Activity Assignment" action="add">
   <related_id>
    <Item type="Identity" action="get">
     <keyed_name>@3</keyed_name>
    </Item>
   </related_id>
  </Item>
 </Relationships>
</Item>